1

I have a joint between two sheets of cement board that forms a small ridge elevated maybe 1/8" relative to the centers of either board. I was wondering if extra thinset on both sides can be used to even it out or is it better to use self-leveling compound beforehand. I am using expensive marble tiles and don't want them to break to an unevenness.

1 Answer 1

3

You may break a few pieces(of marble) just picking them up.

A skim coat on either side of the joint will help.

Block feather with a concrete 'rubbing' block.

My marble floor always have Schluter Ditra under them. I also use it with any questionable floor.

Ceramic tile can tolerate L/360 deflection, stone is twice as sensitive at L/720.

If you have any doubts about floor springiness, use an isolation membrane or stiffen joists or add a beam. Cement board does little for stiffness.

7
  • a skim coat of what?
    – amphibient
    Apr 8, 2013 at 20:59
  • 2
    Thinset mortar.
    – HerrBag
    Apr 8, 2013 at 21:32
  • what if i just dump some self-leveling on either side and wait for it to solidify before setting thinset?
    – amphibient
    Apr 8, 2013 at 21:35
  • as far as Schluter Ditra, do i set that using thinset and then again thinset on top between it and the tile?
    – amphibient
    Apr 8, 2013 at 21:44
  • You can use leveling mortar first. Ditra is set based on the substrate, usually polymer modified thinset over ply or cement board. For most marble, a white thinset is best.
    – HerrBag
    Apr 8, 2013 at 22:59

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.